1. Field of the Invention
The present invention relates to an automatic focus controlling apparatus and, more particularly, to an automatic focus controlling apparatus which is improved such that a photographing lens can be set at an optimal position when information associated with a distance to an object cannot be obtained since, for example, an object has low contrast and low brightness.
2. Related Background Art
As a conventional automatic focus controlling apparatus of this type, an apparatus disclosed in Japanese Patent Publication No. 60-37443 is known. The automatic focus controlling apparatus drives a photographing lens to a predetermined position when information associated with a distance to an object cannot be obtained under the above-mentioned photographing condition (to be referred to as a focus detection impossible state hereinafter). Such a lens position must be arbitrarily set by a photographer in advance.
However, it is troublesome for a photographer to set the lens position, and it is difficult to determine a position to be set.